Evolução paragenética e dos fluidos no depósito Epitermal Cupro-Aurífero Golden Hill, Camaguey, Cuba

摘要: The Cu-Au mineralization at the Golden Hill deposit in Las Tunas Province, Eastern Cuba, is characterized by brecciahosted massive and semi-massive sulfide bodies confined to Crucero Contramaestre Formation Cretaceous Volcanic Arc. enveloped a silicic, argillic advanced alteration assemblage orebodies are particularly associated with latter, typical of high sulfidation epithermal deposits. Within zone, two stages were defined on basis mineralogical textural associations: (i) Stage I quartz–kaolinite–alunite–zunyite–diaspore, disseminated pyrite, enargite and, probably, sub-microscopic Au; (ii) II quartz – natroalunite pyrophyllite, closely related pyrite luzonite famatinite Au. Barite commonly occurs filling fractures cavities may have been introduced late during II. These assemblages indicate that, both stages, took place under conditions low pH ( 10 -32.8 bar) SO 4 - /H 2 S ratios, f > -9.7 bar -8.7 for II, respectively. Additionally, temperatures stage constrained between 250°C 275°C, based coexistence alunite-woodhouseite quartz-kaolinite-diaspore, whereas they varied from 188°C 330°C, according total homogenization fluid inclusions stability pyrophyllite-bearing assemblages. Fluid inclusion investigations, restricted barite, revealed that part presence CO poor (< 0.85 molal), low, but variable, salinity (0,5 9,3 wt% eq. NaCl) aqueous solutions. ample interval values fluids, together Wand Bi-Mo-bearing minerals evidence envisage hydrothermal system as result progressive interaction more diluted lower temperature surface saline higher magmatic This would imply possibilities occurrence shallow epizonal intrusions, which generally considered important sites porphyry mineralization.